﻿// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
// Copyright (c) 2011, Dr. Masroor Ehsan
// All rights reserved.
// 
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above copyright
//       notice, this list of conditions and the following disclaimer in the
//       documentation and/or other materials provided with the distribution.
//     * Neither the name of the author nor the
//       names of its contributors may be used to endorse or promote products
//       derived from this software without specific prior written permission.
// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
// DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// 
// $Author:$
// $Id:$
// $Rev:$
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

using System;

namespace nodatest
{
    public sealed class DistinctTimeZone
    {
        private readonly TimeZoneInfo _tzCurrent;

        public DistinctTimeZone(string timezoneId)
        {
            _tzCurrent = TimeZoneInfo.FindSystemTimeZoneById(timezoneId);
        }

        private DistinctTimeZone(TimeZoneInfo zone)
        {
            _tzCurrent = zone;
        }

        public string TimeZoneId
        {
            get { return _tzCurrent.Id; }
        }

        public string TimeZoneDisplayName
        {
            get { return _tzCurrent.DisplayName; }
        }

        public static DistinctTimeZone SystemDefault()
        {
            return new DistinctTimeZone(TimeZoneInfo.Local);
        }

        public static DistinctTimeZone Universal()
        {
            return new DistinctTimeZone(TimeZoneInfo.Utc);
        }

        public DateTime ZonedNow()
        {
            return UtcToZoned(TimeZoneUtils.UtcNow());
        }

        public DateTime LocalToZoned(DateTime time)
        {
            var zoneTime = TimeZoneInfo.ConvertTime(time, TimeZoneInfo.Local, _tzCurrent);
            //zoneTime = DateTime.SpecifyKind(zoneTime, DateTimeKind.Unspecified);
            return zoneTime;
        }

        public DateTime ZonedToLocal(DateTime time)
        {
            var zoneTime = TimeZoneInfo.ConvertTime(time, _tzCurrent, TimeZoneInfo.Local);
            zoneTime = DateTime.SpecifyKind(zoneTime, DateTimeKind.Local);
            return zoneTime;
        }

        public DateTime UtcToZoned(DateTime time)
        {
            return TimeZoneInfo.ConvertTimeFromUtc(time, _tzCurrent);
        }

        public DateTime ZonedToUtc(DateTime time)
        {
            return TimeZoneInfo.ConvertTimeToUtc(time, _tzCurrent);
        }

        /// <summary>
        /// Converts the local time from another time-zone to this time-zone.
        /// </summary>
        /// <param name="otherZone">The other time-zone.</param>
        /// <param name="otherLocalTime">Local time according to the other time-zone</param>
        /// <returns>Local time according to this time-zone</returns>
        public DateTime ConvertLocalTime(DistinctTimeZone otherZone, DateTime otherLocalTime)
        {
            //return UtcToZoned(otherZone.ZonedToUtc(otherLocalTime));
            return TimeZoneInfo.ConvertTime(otherLocalTime, otherZone._tzCurrent, _tzCurrent);
        }
    }
}